Ala. Code § 40-29-21

Unless another date is specifically fixed by law, the lien imposed by Section 40-29-20 shall arise at the time the assessment list, return therefor or the payment thereof, whichever is prior, was due to have been filed with or made to the Department of Revenue, and shall continue until the liability for the amount so assessed (or a judgment against the taxpayer arising out of such liability) is satisfied or becomes unenforceable by reason of lapse of time.